Evaluation of the Electromyogram of Patients With Myasthenia Gravis

HARVEY AND MASLAND¹(1941) introduced a new technique of clinical electromyography which consisted of stimulating accessible motor nerves percutaneously with supramaximal shocks at any desired frequency and recording the action potentials of the associated muscles. Shortly thereafter Harvey and co-workers, using this method, described a characteristic electromyogram of patients with myasthenia gravis.²More recently, other investigators 3 have employed this test in an evaluation of new therapeutic agents and procedures in the treatment of myasthenia gravis. In the past several years, we have studied 21 patients with myasthenia gravis, using the technique of Harvey and Masland. In this report we summarize our impressions of the value of this procedure as a diagnostic test and as an objective indication of the severity of the myasthenic process. METHODS AND APPARATUS We used the methods of Harvey and Masland¹and of Hodes, Larrabee, and German⁴with these modifications: We